I have had more than a couple of pair of Volkl All Mountain skis that still ski great at 150+ day's I tune my own skis, most of my skis only see the sjop when I can't fix them. I think my AC40's have never been stone ground, I got them in Feb 08. I average 60+ days a season.
My AC4's had over 150 day's on them when I sold them, I should have kept them...
My AX3's had a few less day's because I bent one (day 28) of the first pair I had and volkl sent me new ones.
I have larger size buddy who likes to get the season tune's and he goes through skis much faster then I do.